drm/vmwgfx: Fix a couple of lock dependency violations

[ Upstream commit 5151adb37a5918957f4c33a8d8e7629c0fb00563 ]

Experimental lockdep annotation added to the TTM lock has unveiled a
couple of lock dependency violations in the vmwgfx driver. In both
cases it turns out that the device_private::reservation_sem is not
needed so the offending code is moved out of that lock.

Cc: <stable@vger.kernel.org>
Acked-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>